The way that Apothecary Keever pokes the sheep repeatedly is a reference to the old Warcraft RTS games in which, if you clicked on a critter (including a sheep) enough times, it would eventually explode (but not cause any actual effect on gameplay, so would not modify terrain or harm any units, etc.). Also, the way some units respond to you after being clicked on enough times suggests that in the old Warcraft RTS games, you would actually be poking them when clicking.